This invention relates to friction clutch assemblies in general and is particularly directed to a resiliently loaded lever operating mechanism for these devices.
Lever operating mechanisms for friction type clutches require a certain amount of axial space in order to permit the levers to perform their desired function of engaging and disengaging the clutch. To reduce the axial length of the clutch assembly, it is common practice to provide an annular belleville type spring for applying the required resilient load. One method is to locate the spring internally between the clutch cover and pressure plate with the levers arranged to exert a pull against the pressure plate to overcome the spring load against the pressure plate. Another method used is to position the spring externally between the clutch cover and levers so that the levers carry the full spring load.
The latter design is desirable over the former because the spring is located entirely outside the cover. This eliminates contact between the spring and pressure plate thereby preventing direct conduction of heat from the pressure plate to the spring. Another advantage in this arrangement is the fact that the spring is in constant contact with the levers at all times whether in the releasing or engaging position. This eliminates the need for close fit of the levers or any additional means for holding the levers against rattling. With any design using a spring as described above, it is essential to properly locate the spring relative to the clutch operating parts so that it will function in its intended manner.
While arrangements exist which permit satisfactory operation and control of such springs, they have been complex and require more space than presently available in vehicle applications.